This is a note to let you know that I've just added the patch titled
net: Add non-RCU dev_getbyhwaddr() helper
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-add-non-rcu-dev_getbyhwaddr-helper.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f665a4ef442ca6189b2817e7c3a93543e4d0018a
Author: Breno Leitao <leitao@xxxxxxxxxx>
Date: Tue Feb 18 05:49:30 2025 -0800
net: Add non-RCU dev_getbyhwaddr() helper
[ Upstream commit 4b5a28b38c4a0106c64416a1b2042405166b26ce ]
Add dedicated helper for finding devices by hardware address when
holding rtnl_lock, similar to existing dev_getbyhwaddr_rcu(). This prevents
PROVE_LOCKING warnings when rtnl_lock is held but RCU read lock is not.
Extract common address comparison logic into dev_addr_cmp().
The context about this change could be found in the following
discussion:
Link: https://lore.kernel.org/all/20250206-scarlet-ermine-of-improvement-1fcac5@leitao/
Cc: kuniyu@xxxxxxxxxx
Cc: ushankar@xxxxxxxxxxxxxxx
Suggested-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Link: https://patch.msgid.link/20250218-arm_fix_selftest-v5-1-d3d6892db9e1@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Stable-dep-of: 4eae0ee0f1e6 ("arp: switch to dev_getbyhwaddr() in arp_req_set_public()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d0b4920dee730..f44701b82ea80 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3011,6 +3011,8 @@ static inline struct net_device *first_net_device_rcu(struct net *net)
}
int netdev_boot_setup_check(struct net_device *dev);
+struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type,
+ const char *hwaddr);
struct net_device *dev_getbyhwaddr_rcu(struct net *net, unsigned short type,
const char *hwaddr);
struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type);
diff --git a/net/core/dev.c b/net/core/dev.c
index 90559cb668039..212a909b48405 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -921,6 +921,12 @@ int netdev_get_name(struct net *net, char *name, int ifindex)
return ret;
}
+static bool dev_addr_cmp(struct net_device *dev, unsigned short type,
+ const char *ha)
+{
+ return dev->type == type && !memcmp(dev->dev_addr, ha, dev->addr_len);
+}
+
/**
* dev_getbyhwaddr_rcu - find a device by its hardware address
* @net: the applicable net namespace
@@ -929,7 +935,7 @@ int netdev_get_name(struct net *net, char *name, int ifindex)
*
* Search for an interface by MAC address. Returns NULL if the device
* is not found or a pointer to the device.
- * The caller must hold RCU or RTNL.
+ * The caller must hold RCU.
* The returned device has not had its ref count increased
* and the caller must therefore be careful about locking
*
@@ -941,14 +947,39 @@ struct net_device *dev_getbyhwaddr_rcu(struct net *net, unsigned short type,
struct net_device *dev;
for_each_netdev_rcu(net, dev)
- if (dev->type == type &&
- !memcmp(dev->dev_addr, ha, dev->addr_len))
+ if (dev_addr_cmp(dev, type, ha))
return dev;
return NULL;
}
EXPORT_SYMBOL(dev_getbyhwaddr_rcu);
+/**
+ * dev_getbyhwaddr() - find a device by its hardware address
+ * @net: the applicable net namespace
+ * @type: media type of device
+ * @ha: hardware address
+ *
+ * Similar to dev_getbyhwaddr_rcu(), but the owner needs to hold
+ * rtnl_lock.
+ *
+ * Context: rtnl_lock() must be held.
+ * Return: pointer to the net_device, or NULL if not found
+ */
+struct net_device *dev_getbyhwaddr(struct net *net, unsigned short type,
+ const char *ha)
+{
+ struct net_device *dev;
+
+ ASSERT_RTNL();
+ for_each_netdev(net, dev)
+ if (dev_addr_cmp(dev, type, ha))
+ return dev;
+
+ return NULL;
+}
+EXPORT_SYMBOL(dev_getbyhwaddr);
+
struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type)
{
struct net_device *dev, *ret = NULL;
